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Acquisitions and Dispositions - Schedule of Construction Projects (Details) - SOUTHERN POWER CO	9 Months Ended
	Sep. 30, 2025 MW
Millers Branch Solar Development Phase 1
Business Combination [Line Items]
Approximate nameplate capacity	200
Life output of plant (in years)	20 years
Millers Branch Solar Development Phase 2
Business Combination [Line Items]
Approximate nameplate capacity	180
Life output of plant (in years)	15 years
Millers Branch Solar Development Phase 3
Business Combination [Line Items]
Approximate nameplate capacity	132
Life output of plant (in years)	15 years

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